This invention generally relates to magnetic mixing devices. More specifically, this invention relates to a magnetic mixer of the type wherein a magnetic particle is positioned within a flowing fluid stream. Still more specifically, this invention relates to a magnetic mixer of the type described wherein a coil of conductive material is positioned adjacent to the stream of flowing fluid and is energized by a low voltage oscillating electrical supply to set up an oscillating magnetic field within the flowing stream to thereby oscillate the magnetic particle longitudinally in the flowing stream of fluid.
Magnetic mixers are well known in the art. Examples of such mixers which have a mixing element within the fluid to be mixed may be seen in the following U.S. Pat. Nos. 2,641,452; 3,689,033; and 3,793,886. However, these mixers have not proven completely acceptable in automatic biological fluid measurement systems. In particular, many new devices have been developed for automatic human blood analysis. In these systems, very small blood samples are mixed with buffers, reagents or other fluids. The mixed fluid stream is then subjected to testing for various attributes of the blood sample. These systems are generally designed to be "flow through" type systems to increase the speed of measurement. This requires accurate and repeatable mixing of the blood sample and any other fluid used while these fluids are flowing. Since the sample sizes are usually kept quite small, this requires a small, simple, reliable and, if possible, inexpensive mixing device. Many of the prior art devices operated at relatively high voltages which imparted a very undesirable heating effect to the samples under measurement. We have devised a magnetic mixing device which is quite small, yet reliable and efficient. This device will operate on low voltages and is relatively inexpensive to manufacture.